Beiträge zur Chemie der Elemente Niob und Tantal. 81. Niob- und Tantalkomplexe mit der anionischen Gruppe {[Me6X12]X}; X = Cl,Br

The compounds A₄Nb₆Cl₁₂]Cl₆ (A ? Na, K, Cs), K₄Nb₆Br₁₂]Br₆ and A₄Ta₆Cl₁₂]Cl₆ (A ? Na, K, Cs) are prepared. The chemical equations for formation and decomposition are taken into consideration. The complexes Nb₆Br₁₂]²⁺ and Ta₆Cl₁₂]²⁺, unstable in the binary systems, are stabilized in the ternary compounds. The compounds are isotypic with the known K₄Nb₆Cl₁₂]Cl₆. For some of them lattice constants and molecular volumes are communicated.